1. Field of the Invention
The present invention relates to a push-button apparatus which can be rotated about a rotation axis, and which functions as a switching device.
2. Related Art
FIG. 1 is a front view showing a construction of a front panel of a car-audio apparatus. In the FIG. 1, reference numeral 1 denotes a slot. This slot 1 is formed at approximately central portion of a front panel (hereinafter referred to panel) P as a case body of the car-audio apparatus. The slot 1 is used to lead a plurality of compact discs (hereinafter referred to CDs) to a CD driving apparatus (not shown) in the car-audio apparatus. A plurality of push-buttons 2 are arranged at a portion beneath the slot 1 of the panel P. Each push-button 2 is used to select a required CD from the group of the CDs above.
The push-button 2 has a hinge offset from the center of symmetry. More specifically, as shown in FIG 2, the push-button 2 includes a box-type main body 3 having an upper portion functioned as an operation face 3a, both side-walls 3b and 3c, front wall 3d and rear wall 3e. A pair of bearing portions 4 are dangled from the lower part of the both side-walls 3b and 3c, respectively, near the rear wall 3e. Each bearing portion 4 has a bearing hole 4a as a center of rotation. The push-button 2 is, as shown in FIG. 4, arranged within a space defined between inside-walls SW of the panel P. As shown in FIG. 3, the panel P has a pair of rotation axes P1 in the space of the panel P. One axis P1 is extended to the other axis P1. Both axes P1 are rotatably arranged in the bearing hole 4a of bearing portion 4. Further, the panel P has a hole P2 which can be engaged with a claw portion 5. The claw portion 5 is dangled from the lower part of the front wall 3d. A lower end of the claw portion 5 is contact with a top of a member S1 of a switching mechanism S on a printing circuit board B arranged beneath the panel P. In case that the member S1 per se is made from elastic materials such as gums, the member S1 is upwardly urged by a return force on the basis of the elastic material. Alternatively, the member S1 may be upwardly urged by a return force on the basis of a spring (not shown) arranged in the switching mechanism S. In any case, the member S1 is upwardly urged in a direction of arrow Al as illustrated in FIG. 3 to elevate the claw portion 5 and to engage with the hole P2 of the panel P. One terminal (not shown) is arranged at a lower portion of the member S1, and the other terminal (not shown) is fixed on the printing circuit board B in the switching mechanism S. Both terminals (not shown) are away from each other by virtue of the urging force.
Movement of the push-button 2 will be described as follows:
When the upper portion of the main body 3 is downwardly pushed in a direction of arrow A2 of FIG. 3, the main body 3 is rotated in a direction of arrow A3 of FIG. 3 about the bearing portion 4 and the rotation axis P1 as the center of rotation. In this case, the member S1 of the switching mechanism S is downwardly pushed against the urging force by the claw portion 5 of the main body. As a result, the one terminal (not shown) of the member S1 comes into contact with the other terminal (not shown) to change over from xe2x80x9cswitch-onxe2x80x9d to xe2x80x9cswitch-offxe2x80x9d or the reverse.
Next, when pushing force subjected to the upper portion of the main body 3 is weakened or eliminated, the main body 3 is rotated by the urging force of the member SI in a direction of arrow A4 of FIG. 3. In this case, since the one terminal (not shown) of the member Si is elevated in the direction of arrow A1, the one terminal (not shown) is away from the other terminal (not shown) to change over from xe2x80x9cswitch-offxe2x80x9d to xe2x80x9cswitch-onxe2x80x9d or the reverse. Simultaneously, since the claw portion 5 is elevated by the urging force of the member S1 in the direction of arrow A1 to engage with the hole P2 of the panel P, the rotation of the main body 3 in the direction of arrow A1 is restricted by such engagement.
As shown in FIG. 4, it is however necessary to define a gap between the side-wall 3b or 3c of the main body 3 and the inside-walls SW of the panel P in order to rotate smoothly the push-button 2. Since the bearing portion 4 of the push-button 2 is slightly slid in a longitudinal direction on the rotation axis P1 of the panel P, the main body 3 comes into contact with the panel P on sliding. This contact makes operators feel that the push-button is unstable. As a result, there was a problem that reliability regarding the movement of switching was reduced.
Accordingly, it is an object of the present invention to provide a push-button apparatus having a high reliability regarding the movement of switching without coming into contact the main body with the panel.
According to a first aspect of the present invention we provide a push-button apparatus including a main body having at least two inward walls parallel to each other; a push-button having two outward walls parallel to each other, the push-button being arranged within an inner space defined between the two inward walls of the main body; a recess arranged at any one of the main body and the push-button; and a rotation axis arranged at the other of the main body and the push-button and rotatably fitted into the recess, wherein a front end of the rotation axis pressingly comes into contact with a bottom of the recess by virtue of elastic return force derived from materials of the push-button.
According to a second aspect of the present invention we provide a push-button apparatus above, wherein a sliding-resistance member is arranged at least any one of the front end of the rotation axis and the bottom of the recess.
According to a third aspect of the present invention we provide a push-button apparatus above, wherein a tapered projecting part is arranged at any one of the front end of the rotation axis and the bottom of the recess, and wherein the tapered projecting part is positioned at a central line of the rotation axis.